Topics

To the Editor: In their article on controlled trials, Forder et al1 described the trial by Karlowski et al on vitamin C and the common cold2 as an example of how patients’ or investigators’ preconceptions about the value of the treatment may affect a trial’s results. However, their presentation of this trial is misleading in two respects.

The full article is accessible to AMA members and paid subscribers. If you are an AMA member or have a subscription login to read more or purchase a subscription now.